Asthma Treatment Response Modified by PM2.5, NO2, and O3 Among African American Children: A Reanalysis of the AsthmaNet's BARD Trial.

Journal: The Journal Of Allergy And Clinical Immunology
Published:
Abstract

Background: Asthma morbidity significantly affects children of all racial backgrounds; however, African American children experience a greater disease burden than children from other racial groups. Despite the known influence of air pollution on asthma outcomes, its role in the efficacy of asthma treatments remains underexplored.

Objective: To examine how exposure to particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3) influenced treatment outcomes in the NIH AsthmaNet Best African American Response to Asthma Drugs (BARD) trial.

Methods: The BARD trial randomized 224 African American children to four asthma treatments consisting of inhaled corticosteroids (ICS) and long-acting beta antagonists (LABA) administered in a randomized crossover fashion. Treatment efficacy was assessed by the frequency of asthma exacerbations, percent predicted FEV1 (%PFEV1), and annualized asthma control days. Residential exposures to PM2.5, NO2, and O3 were estimated using a validated spatiotemporal model. Mixed effects models were used to evaluate the interaction between pollution exposure and treatment efficacy, adjusting for age, household triggers and trial site.

Results: PM2.5, NO2, and O3 exposures ranged substantially across participants: from 2.28 - 15.3 μg/m3, 2.34 - 63.7 ppm, and 2.57 - 23.7 ppb, respectively. NO2 and PM2.5 exposures were not associated with increased exacerbations post-treatment (p for interaction = 0.15 and 0.08, respectively). However, NO2 exposure significantly modified the effect of high-dose ICS+LABA therapy on lung function. Children with below median NO2 exposures while on ICS + LABA had a reduction of 5.86 (1.16, 10.56) in %PFEV1 compared to those with above-median NO2 exposures.

Conclusions: Residential high NO2 exposure may significantly attenuate the efficacy of ICS+LABA therapy on lung function in African American children. These findings suggest the need to consider environmental factors in clinical trials and asthma management strategies.

Authors
Lizbeth Gómez, Ellen Kinnee, Michael Young, Joel Kaufman, Anne Fitzpatrick, Sharmilee Nyenhuis, Julian Solway, Steven White, Edward Naureckas, Wanda Phipatanakul, Michael Wechsler, Susan Kunselman, David Mauger, Leslie Mcclure, Usama Bilal, Stephen Lazarus, Fernando Holguin, Jane Clougherty
Relevant Conditions

Asthma